Double-ended threading-die.



J. E. BULLOCK.

DOUBLE ENDED THREADING DIE.

APPLICATION FILED DEC.27, 1915.

1,186,276. Patented June 6,1916.

UNITED STATES PA TENT OFFICE. l

JAMES E. BULLOCK, OF NEW HAVEN, CONNECTICUT, ASSIGNOR TO THE GEOMETRICTOOL 60., OF NEW HAVEN,- CONNECTICUT, A CORPORATION.

DOUBLE-ENDED THREADING-DIE.

Specification of Letters Patent. Patnted J ne 6 1916.

Application filed December 27,1915. 'Serial No. 68,709. i

To all whom it may concern:

Be it known that I, JAMES E. BULLOCK, a citizen of the United States,residing at New Haven, in the county of New Haven and State ofConnecticut, have invented a new and useful Improvement in Double- EndedThreading-Dies; and I do hereby declare the following, when taken inconnection with the accompanying drawings and the characters ofreference marked there on, to be a full, clear, and exact description ofthe same, and which said drawings constitute part of this application,and represent, in I Figure la face view of a double-ended threading dieor chaser constructed in accordance with my invention. Fig. 2 an edgeView thereof. Fig. 3 an end view thereof. Fig. 4. an edge view of one ofthe modified forms which my improved threading die or chaser may assume.

My invention'relates to an improvement in threading-dies or chasers, theobject being to produce a threading-die or chaser of Snperiorconvenience and economy, and de signed with particular reference for usein the automatically opening die-heads of screw-cutting machinesemployed in the manufacture of screws and screw-machine products, asdistinguished from threading dies or chase'rs designed for use inportable hand-operated threading-die stocks and kindred tools.

With these ends in view, my invention consists in a double-endedthreading-die or chaser formed at its respective ends with cutting teethlocated diametrically opposite each other, and also formed at itsrespective ends with transverse clearance-notches located diametricallyopposite each other, the said die being alsoformed in its respectivefaces withoppositely located longitudinal key-receiving grooves and inone of its edges with two retaining cam-receivmg slots placed onopposite sides of the transverse center of the die.

In carrying out my invention as herein shown, my improved double-endedthreading-die or chaser is formed at its respectlve ends with cuttingteeth 2 and 3 corresponding in pitch and in size as to; fineness orcoarseness, but located diametrically opposite each other with respectto the lon l tudinal axis of the die. I prefer to have t e inwardadjacent to its longitudinal axis by the formation at the ends ofthe dieof clearance-notches 4 and 5 also placed diametrically opposite eachother. The respective faces 8 and 9 of the die are formed withcorresponding, oppositely located longitudinal key-receiving grooves 10and 11 which receive the keys with which the diehead is provided forpositioning the dies therein. One edge of the die is also formed withtwo corresponding, inclined transverse cam-receiving slots 12 and 13located on either side of the transverse center of thedie and designedto receive the operatingcams with which the die-heads are provided forholding the dies therein and operating them.

The modified form of die 14 shown in Fig.

4, corresponds to the die of Figs. 1, 2 and 3 in every respectexceptthat the cuttingteeth 15 and 16 at its respective ends, are curvedinstead of straight, these teeth being conformed in curvature to thecurvature of the object which they are designed to thread.

Under the specific construction above described, I secure superiorconvenience, since the die, when worn at one end, may be readilyreversed and the other end used. Then both ends of the die may havetheir cutting teeth reground with less outlay of time and labor thanwould be required to regrind the cutting edges of separate dies.Furthermore, by my invention, I secure a great economy, since withoutmaterially adding to the amount of high speed steelin one die, Ivirtually convert it into two dies.

By locating the cam-receiving slots in the same edge of the die onopposite sides of its transverse center, I secure all of the advantagesof a reversible die or chaser without impairing its strength, since thetransverse sectional area of the die isnot reduced by a plurality ofcam-receiving slots as long as they are all located'in one of its edgeswhereas when the slots are located in both of its edges, the strength ofthe die is materially impaired. a

I am aware that a double-ended-threading-die is not broadly new, andclaim only my particular construction.

I claim z. A double-ended threading-die or chaser for use in theautomatically opening heads of screw-cutting machines, thesaid diediebeing characterized by having its respective head, whereby the chaseris made reversible ends formed With cutting-teeth, and further end forend in an automatically opening characterized by having twocorresponding die-head provided with a cam arranged for 10 cam-receivingslots respectively located at cooperation with a non-reversible die 01.

5 equal distances from its cutting teeth and chaser having a cam-slotlocated in one of formed in one and the same edge of the its ends. diefor the reception of the cam in the die- J. E. BULLOCK.

